Praying for the salvation of all the people of Bulgaria seem to be both abstract and overwhelming. Because of this, you may want to consider praying for people by name, and/or praying in the following more specific ways (adapted from the Navigators):
That God would draw them to himself through Jesus: “No one can come to me unless the Father who sent me draws him, and I will raise him up at the last day. It is written in the Prophets: ‘They will all be taught by God.’ Everyone who listens to the Father and learns from him comes to me.” (John 6:44-45).
That they would believe that God exists and earnestly seek Him: “And without faith it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him” (Hebrews 11:6).
That they would accept the Bible as the Word of God: “And we also thank God continually because, when you received the word of God, which you heard from us, you accepted it not as the word of men, but as it actually is, the word of God, which is at work in you who believe” (1 Thessalonians 2:13).
That God would restore their spiritual sight: “The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel of the glory of Christ, who is the image of God” (2 Corinthians 4:4).
For the work of the Holy Spirit in their lives: “When he comes, he will convict the world of guilt in regard to sin and righteousness and judgment … But when he, the Spirit of truth, comes, he will guide you into all truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come” (John 16:8,13).
That God would send spiritual workers to them: “When he saw the crowds, he had compassion on them, because they were harassed and helpless, like sheep without a shepherd. Then he said to his disciples, ‘The harvest is plentiful but the workers are few. Ask the Lord of the harvest, therefore, to send out workers into his harvest field'” (Matthew 9:36-38).
That they would repent and experience times of refreshing from God: “Repent, then, and turn to God, so that your sins may be wiped out, that times of refreshing may come from the Lord” (Acts 3:19).
That they would freely confess Christ Jesus as Lord: “That if you confess with your mouth, ‘Jesus is Lord,’ and believe in your heart that God raised him from the dead, you will be saved. For it is with your heart that you believe and are justified, and it is with your mouth that you confess and are saved” (Romans 10:9-10).
That they would no longer live for themselves, but for Christ: “And he died for all, that those who live should no longer live for themselves but for him who died for them and was raised again” (2 Corinthians 5:15).
That they would grow in Christ and overflow with thankfulness: “So then, just as you received Christ Jesus as Lord, continue to live in him, rooted and built up in him, strengthened in the faith as you were taught, and overflowing with thankfulness” (Colossians 2:6-7).
Thank you for praying with us for the salvation of all the people of Bulgaria!